03a lighting

Energy Audit for Commercial Buildings(Lighting System)

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Outline:Outline:

Introduction

Types of lighting systems

Assessment of lighting systems

Energy efficiency opportunities

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IntroductionIntroduction

• Lighting energy consumption

• 20-45% in commercial buildings

• 3-10% in industrial plants

• Significant energy savings can be realized with a minimal capital investment

Background

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• Light: electromagnetic waves in space

• Light is emitted through:

a) Incandescence

b) Electric discharge

c) Electro luminescence

d) Photoluminescence

Basic Theory

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Definitions and Common Terms Lumen

• 1 lumen = the photometric equivalent of the watt

• 1 lumen = luminous flux per m2 of a sphere with 1 m radius and a 1 candela isotropic light source at the centre

• 1 watt = 683 lumens at 555 nm wavelength

Lux

• metric unit of measure for illuminance on a surface: 1 lux = 1 lumen / m2

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Definitions and Common Terms Luminous intensity (I)

• measured in Candela (cd)

Luminous flux (lm)

• 4π x luminous intensity

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Definitions and Common Terms Installed load efficacy

• Average maintained illuminance on a working plane: lux/W/m2

Installed load efficiency ratio

• Target load efficacy / Installed load

Rated luminous efficacy• Rated lumen output of the lamp / rated power consumption

• Lumens per watt

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Definitions and Common Terms

Room index• Ratio for the plan dimensions of the room

Target load efficiency• Installed load efficacy considered achievable under best efficiency

• Lux/W/m²

Utilization factor • A measure of the effectiveness of the lighting scheme

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E = I / d2

E1 d12 = E2 d22

E = I / d2

E1 d12 = E2 d22



The inverse square law• Defines the relationship between illuminance from

a point source and distance

E = Iluminance

I = Luminous intensity

d = distance

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Color temperature

• Color appearance of a lamp and the light it produces

• Measured in Kelvin (K)

• Incandescent lamps: “true value” color temperature

• Fluorescent and high intensity discharge (HID) lamps: correlated color temperature

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Definitions and Common Terms Color rendering index (CRI)

Color rendering

groups

CIE general color rendering Index(Ra)

Typical application

1A Ra > 90 Wherever accurate color rendering is required e.g. color printing inspection

1B 80 < Ra < 90 Wherever accurate color judgments are necessary or good color rendering is required for reasons of appearance e.g. display lighting

2 60 < Ra < 80 Wherever moderate color rendering is required

3 40 < Ra < 60 Wherever color rendering is of little significance but marked distortion of color is unacceptable

4 20 < Ra < 40 Wherever color rendering is of no importance at all and marked distortion of colour is acceptable

Table 1. Applications of color rendering groups (Bureau of Energy Efficiency, 2005)

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Outline:Outline:

Introduction




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Types of Lighting SystemsTypes of Lighting Systems

• Incandescent lamps

• Tungsten Halogen Lamps

• Fluorescent lamps

• High pressure sodium lamps

• Low pressure sodium lamps

• Mercury vapour

• Metal halide

• Blended

• LED lamps

HID lamps

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Incandescent Lamps

• Emit radiation mainly in the visible region

• Bulb contains vacuum or gas filling

• Efficacy: 12 lumen / Watt

• Color rendering index: 1A

• Color temperature: 2500 – 2700 K

• Lamp life <2000 hrs (BEE India, 2005)

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Tungsten-Halogen Lamps• Tungsten filament and a halogen gas

filled bulb

• Tungsten atoms evaporate from the hot filament and move to cooler wall of bulb

• Efficacy: 18 lumens/Watt

• Color rendering index: 1A

• Color temperature: warm

• Lamp life < 4000 hrs

Tungsten halogen lamps (BEE India, 2005)

• Advantages:• More compact• Longer life• More and whiter light

• Disadvantages:• Cost more• Increased IR and UV

• Handling problems

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Fluorescent Lamps• 3 – 5 times as efficient as standard incandescent

lamps and last 10 – 20 times longer

• Electricity passes through a gas or metallic vapor and causes radiation

• Fluorescent tubes are hot cathode lamps

(BEE India, 2005)

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Fluorescent Lamps

• Different types (T12, T10, T8 and T5) differing in diameter and efficiency

• Most efficient at ambient temperature of 20-30 oC,

• Compact fluorescent lamps (CFL) have much smaller luminaries Compact fluorescent lamp (CFL)

(BEE India, 2005)

Features:

Halo-phosphate• Efficacy – 80 lumens/Watt (HF

gear increases this by 10%)

• Color Rendering Index –2-3• Color Temperature – Any• Lamp Life – 7-15,000 hours

Tri-phosphor

• Efficacy – 90 lumens/Watt• Color Rendering Index –1A-1B• Color Temperature – Any

• Lamp Life – 7-15,000 hours

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High Pressure Sodium (HPS) Lamps

BEE India, 2005

• Used in outdoor and industrial applications

• Consist of: ballast, high- voltage electronic starter, ceramic arc tube, xenon gas filling, sodium, mercury

• No starting electrodes

• High efficacy: 60 – 80 lumen/Watt

• Color rendering index: 1 - 2

• Color temperature: warm

• Lamp life < 24,000 hrs

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Low Pressure Sodium (LPS) Lamps• Commonly included in the HID family

• Highest efficacy: 100 - 200 lumen/Watt

• Poorest quality light: colors appear black, white or grey shades

• Limited to outdoor applications

• Efficacy: Color rendering index: 3

• Color temperature: yellow

• Lamp life < 16,000 hours

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Mercury Vapor Lamps

• Oldest HID lamp

• Consists of: arc tube with mercury and argon gas and quartz envelope, third electrode, outer phosphor coated bulb, outer glass envelope

• Long life and low initial costs

• Very poor efficacy: 30 – 65 lumens/Watt

• Color rendering index: 3

• Color temperature: intermediate

• Lamp life: 16000 – 24000 hours

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© UNEP 2006© UNEP 2006


Metal Halide Lamps

BEE India, 2005

• Works similar to tungsten halogen lamps

• Largest choice of color, size and rating

• Better efficacy than other HID lamps: 80 lumen/Watt

• Require high voltage ignition pulse but some have third electrode for starting

• Color rendering index: 1A – 2

• Color temperature:3000 – 6000 K

• Lamp life:6000 – 20,000 hours

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Blended Lamps

• “Two-in-one”: 2 light sources in 1 gas filled bulb

• Quartz mercury discharge tube

• Tungsten filament

• Suitable for flame proof areas

• Fit into incandescent lamps fixtures

• Efficacy: 20 – 30 lumen/Watt

• Lamp life < 8000 hours

• High power factor: 0.95

• Typical rating: 160 W

BEE India, 2005

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LED Lamps• Newest type of energy efficient lamp

• Two types: • red-blue-green array• phosphor-coated blue lamp

• Emit visible light in a very narrow spectrum and can produce “white light”

• Used in exit signs, traffic signals, and the technology is rapidly progressing

• Significant energy savings: 82 – 93%

• Longest lamp life: 40,000 – 100,000 hours

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Reflectors• Impact how much light reaches

area and distribution pattern

• Diffuse reflectors:

• 70-80% reflectance but declining in time

• painted or powder coated white finish

• Specular reflectors:

• 85-96% reflectance and less decline in time

• Polished or mirror-like

• Not suitable for industrial open-type strip fixtures

BEE India, 2005

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Gear

• Ballast

• Current limiting device

• Helps voltage build-up in fluorescent lights

• Ignitors

• Start metal halide and sodium vapor lamps

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Comparing lamps

Type of Lamp

Lum / Watt Color

Rendering Index

Typical ApplicationLife

(Hours)Rang

e

Avg.

Incandescent 8-18 14 Excellent Homes, restaurants, general lighting, emergency lighting

1000

Fluorescent Lamps 46-60 50 Good w.r.t. coating

Offices, shops, hospitals, homes

5000

Compact fluorescent lamps (CFL)

40-70 60 Very good Hotels, shops, homes, offices

8000-10000

High pressure mercury (HPMV)

44-57 50 Fair General lighting in factories, garages, car parking, flood lighting

5000

Halogen lamps 18-24 20 Excellent Display, flood lighting, stadium exhibition grounds, construction areas

2000-4000

High pressure sodium (HPSV) SON

67-121

90 Fair General lighting in factories, ware houses, street lighting

6000-12000

Low pressure sodium (LPSV) SOX

101-175

150 Poor Roadways, tunnels, canals, street lighting

6000-12000

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Outline:Outline:

Introduction




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Assessment of Lighting SystemsAssessment of Lighting Systems

Designing with Light

• Better lighting: increased productivity

• Two main questions for designer:

• Choose correct lighting level

• Choose quality of light (color rendering)

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Designing with Light

Illuminance level (lux)

Examples of Area of Activity

General Lighting for rooms and areas used either infrequently and/or casual or simple visual tasks

20 Minimum service illuminance in exterior circulating areas, outdoor stores , stockyards

50 Exterior walkways & platforms.

70 Boiler house.

100 Transformer yards, furnace rooms etc.

150 Circulation areas in industry, stores and stock rooms.

General lighting for interiors

200 Minimum service illuminance on the task

300 Medium bench & machine work, general process in chemical and food industries, casual reading and filing activities.

450 Hangers, inspection, drawing offices, fine bench and machine assembly, colour work, critical drawing tasks.

1500 Very fine bench and machine work, instrument & small precision mechanism assembly; electronic components, gauging & inspection of small intricate parts (may be partly provided by local task lighting)

Additional localized lighting for visually exacting tasks

3000 Minutely detailed and precise work, e.g. Very small parts of instruments, watch making, engraving.

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Recommended Illuminance Levels Scale of illuminance

• Illuminance for all non-working interiors > 20 Lux

• Factor 1.5 is the smallest significant difference in effect of illuminance

• Therefore the following scale is recommended:

20–30–50–75–100–150–200–300–500–750–1000 –1500–2000, …Lux

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Recommended Illuminance Levels

Illuminance ranges recommended for interior or activity

• Middle value (R) for working interiors

• Higher value (H) for visual work

• Lower value (L) where accuracy is non-important

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Methodology for Efficiency Study• Step 1: Make inventory of lighting system

elements and transformers

S. No.

Plant Locati

on

Lighting Device &

Ballast Type

Rating in Watts Lamp

& Ballast

Population Numbers

Use / Shifts as I / II / III shifts / Day

S. No.

Plant Locatio

n

Lighting Transformer Rating

(kVA)

Numbers Installed

Measurement Provisions Available Volts / Amps /

kW/ Energy

Table: Device rating, population and use profile

Table: Lighting transformer/rating and population profile

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Methodology for Efficiency Study

• Step 2: Measure and document the Lux levels

• Step 3: Measure and document the voltage and power consumption at input points

• Step 4: Compare the measured Lux values with standard values as reference

• Step 5: Analyze the failure rates of lamps, ballasts and the actual life expectancy levels

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Methodology for Efficiency Study

Step-6 : identify improvement options, for example:

• Maximum sunlight use options through transparent roof sheets

• Replacements of lamps and ballasts to more energy efficient types

• Selecting interior colors for light reflection

• Modifying layout as per needs

• Providing individual / group controls for lighting

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Training Agenda: ElectricityTraining Agenda: Electricity

Introduction




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Energy Efficiency Opportunities Energy Efficiency Opportunities

Use Natural Day Lighting

• North lighting

• Glass strips across the roof

• Sky lights with fiber reinforced plastic (FRP)

• Atrium with FRP dome

• Natural light fromwindows

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De-lamping to Reduce Excess Lighting

• Effective method to reduce energy consumption

• Reducing lamp height combined with de-lamping: illuminance hardly affected

• Complicated for series wired ballasts

• Less problematic with parallel wired ballast


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Task Lighting

• Low wattage lamps at task

• General illuminance at lower level

• Benefits:

• Reduce number of lighting fixtures

• Reduce lamp wattage

• Save considerable energy

• Better illuminance

• Aesthetically pleasing ambience


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High Efficiency Lamps & Luminaries

Examples (9 – 75% savings):

• Metal halide lamps to replace mercury / sodium vapor lamps

• HPSV lamps where color rendering is not critical

• LED panel indicator lamps to replace filament lamps

• Luminaries with mirror optics instead of conventional painted ones


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Reduction of Lighting Feeder Voltage

• Can save energy

• Provided drop in light output is acceptable

Per

cen

tag

e

Supply voltage percentage

1) Lamp current 2) Circuit power, 3) Lamp power, 4) Lamp output 5) lamp voltage 6) lamp efficiency

Effect of voltage variation of fluorescent tube light parameters (BEE India, 2005)

1

2

3

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12

3

4

5

6

6


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Electronic Ballasts instead of Electromagnetic Ballasts

• Oscillators that convert supply frequency to about 20,000 – 30,000 Hz

• Available for fluorescent tube lights, LPSV and HPSV lamps

• Benefits in fluorescent tube lights:• Reduced power loss: 1 Watt instead of 10-15

Watt• Improved efficacy at higher frequencies• Elimination of starter: no flickering


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Low Loss Electromagnetic Ballasts for Tube Lights

Loss per tube lights:

• Standard ballasts: 10 – 15 Watts

• Low loss ballasts: 8 - 10 Watts


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Timers, Twilight Switches & Occupancy Sensors

• Timers: switching of unnecessary lights

• Twilight switches: depending on availability of daylight

• Occupancy sensors: depending on presence of people

• Applicable for general areas, conference rooms, cubicles, restrooms, exteriors


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T5 Fluorescent Tube Light

• Slimmer tubes than T12 and T8 tubes

• Improved luminaire efficiencies by 7%, and with super-reflective aluminum luminaire by 11-30%

• Mercury reduction: 3 mg instead of 15 mg per lamp

• Can only be operated with electronic ballasts and not existing luminaries


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Lighting Maintenance

• Light levels decrease >50% due to aging lamps and dirt on fixtures, lamps and room surfaces

• Maintenance options:

• Clean equipment

• Replace lenses

• Keep spaces bright and clean

• Re-lamping


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THANK YOUTHANK YOU

FOR YOUR ATTENTIONFOR YOUR ATTENTION

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Disclaimer and ReferencesDisclaimer and References

• This PowerPoint training session was prepared as part of the project “Greenhouse Gas Emission Reduction from Industry in Asia and the Pacific” (GERIAP). While reasonable efforts have been made to ensure that the contents of this publication are factually correct and properly referenced, UNEP does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. © UNEP, 2006.

• The GERIAP project was funded by the Swedish International Development Cooperation Agency (Sida)

• Full references are included in the textbook chapter that is available on www.energyefficiencyasia.org

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03a lighting